Suppose the formula in A1 is =A1+1. What should be the displayed value in A1? How long should it take to display that number? This is a simple case, which cl

Suppose the formula in A1 is =A1+1. What should be the displayed value in A1? How long should it take to display that number? This is a simple case, which clearly diverges. There is no simple way to determine from a general formula whether it will be convergent or divergent. In the interests of definiteness, Excel defaults to just disallowing formulae with this kind of indecisive output.